Many manufacturing or assembly processes require an environment which is free of particulates or other contaminants to at least a certain degree. Clean rooms have long been used in the semiconductor industry for the processing of wafers from which semiconductor devices are formed. Other industries which have used clean rooms include computer disk drive manufacturers. Certain disk drive parts are manufactured in a clean room environment, while other parts are manufactured and then cleaned prior to entry into a clean room for incorporation into some type of an assembly within the clean room (e.g., an actuator arm assembly).
One alternative to clean rooms which has been used at least in the computer disk drive industry is a so-called minienvironment. Minienvironments effectively are a self-contained unit which may be disposed within or outside of a clean room and which provide clean room-like air qualities. A representative example of a minienvironment is disclosed in U.S. Pat. No. 5,487,768 to Zytka et al., which is owned by the assignee of this patent application, and which is incorporated by reference in its entirety herein. Generally, a minienvironment is an enclosure of sorts which has its own forced air system for delivering filtered air into the noted enclosure. Various types of access may be provided to the minienvironment and through which this air may be discharged along with any particulates or other contaminants contained therein. These accesses or fluid interconnections with the surrounding environment are typically disposed on a lower portion of the minienvironment, and the filtered air is typically introduced into the minienvironment in an upper portion thereof.
Smaller-sized openings may be provided in the minienvironment's enclosure to allow an operator to dispose his or her arms therethrough to retrieve parts and/or to execute some type of operation (e.g., assembly) within the minienvironment. Only the operator's hands and possibly a portion of the operator's arms need to meet certain cleanliness requirements with this type of minienvironment. It should be appreciated that these types of minienvironments thereby do not provide for total isolation from the surrounding environment, but instead rely on a higher air pressure within the minienvironment's enclosure to keep particulates and other contaminants which may exist in the surrounding environment from flowing into the minienvironment through the noted fluid interconnections. The above-noted reference to an "enclosure" for a minienvironment would thereby include a shroud, hood, or the like which does not provide for a total enclosure (e.g., a gap may exist along a lower portion of a sidewall of the ninienvironment). Some minienvironments may include a glove box or the like to further maintain the cleanliness within the minienvironment and for the above-noted types of purposes. Still other minienviromnents have no access for operations personnel during normal operations within the minienvironment, but instead rely on robotic devices within the minienvironment to perform the desired operation(s) therewithin. In both of these later instances, there may be a total isolation of the interior of the minienvironment from the surrounding environment.
There are rather significant costs associated with the operation of both clean rooms and minienvironments. Simply put, the various actions which are undertaken in order to maintain the desired level of cleanliness often come at a rather significant financial cost. Both personnel and all other materials (e.g., parts to be used in an assembly being executed in the clean room/minienvironment) which enter the clean room or the minienvironment must be within the desired cleanliness level. U.S. Pat. Nos. 5,713,791 and 5,344,365 both address rather extravagant systems/methods directed to the transfer of materials to/from/within a clean room environment. So-called "clean carts" have also been used to transfer materials from outside a clean room to a location therein. Known clean carts are simplistically a box with an access door on a side thereof (i.e., the top is non-removable in these units). Cleaned parts are loaded into this "box" through the access door. Filtered air is simultaneously blown into the "box" during loading through this access door as well. All intended discharges from within the "box" at this time are also through this same access door as there are no other designed perforations in the clean cart. Once the clean cart is loaded, the door is closed to seal the interior of the same and it may then be wheeled into the clean room. Typically these clean carts are parked next to a station which uses the parts contained therein in some manner.
Numerous disadvantages exist in relation to known clean carts. One is that these clean carts consume floor space which in some cases may be at a premium. Another is that the operator must manually retrieve parts from the clean cart and provide the same to the subject workstation. Often this involves certain repetitive motions which may subject the operator to injury over time. For instance, an operator positioned on a chair at a minienviromnent may have to rotate 90.degree. and bend over to access the parts contained within the clean cart, and thereafter rotate back to the minienvironment with the parts in hand (typically on a tray) to position them into the minienvironment. The alternative would be for the operator to get up and walk over to the clean cart which not only wastes valuable time, but possibly means positioning the clean cart at a location where there may be unanticipated impacts between the clean cart and personnel which would be undesirable in a number of respects.